The invention relates to an electrical machine having a fan impeller.
AC generators for motor vehicles which are cooled with the aid of a fan impeller during operation in order to be able to maintain a temperature at which optimum power is ensured are known. A generator of this kind which is provided with a fan impeller is described, for example, in DE 692 01 498 T2. The fan impeller which is known from said document comprises an annular metal insert part and a blade support ring which is in the form of a molded plastic part and has fan blades. The blade support ring is formed on the metal insert part which has a central recess in order to be mounted on a shaft. The annular insert part is virtually completely surrounded by the plastic of the blade support ring, this having the disadvantage that, on account of the insulating properties, heat cannot be effectively dissipated, this heat spreading from the shaft on which the fan ring is seated.
U.S. Pat. No. 5,977,668 discloses an AC generator having a fan impeller which has a plastic blade support ring with fan blades formed on it and also has a metal insert part which forms a hub in order to be mounted on a shaft, with the plastic blade support ring forming the radially outer part and the insert part forming the radially inner part of the fan impeller. In this embodiment, care should be taken that there is sufficient adhesion between the plastic of the blade support ring and the metal of the insert part even with changing external conditions, in particular at different temperatures. It is necessary to ensure that, for example in the event of changes in temperature, the blade support ring does not accidently become detached from the insert part.